Removal of asphaltic constituents from hydrocarbon oil



March 14.. 1950 w. KlERsTED, JR

REMOVAL 0F ASPHALTIC CONSTITUENTS FROM HYDRCARBON OIL Filed Maren 12,1947 Patented Mar. 14, 1950 UNITED STATES PATE/N REMOVAL '0F ASIHALTIClCONSTITUENTS. FROM`-HYDROCARBON OIL WynkoolnKiersted; Jr., Scarsdale,-N;Y., assigner f to Texaco DevelopmentCorporation, New-York;- y N. .Y.,yacorporationcf Delaware Application'v March l2, 1947, Serial No. 734,092@i The invention broadly contemplatesa:contin-` o uous countercurrent-m'ethod ofv removing asadapted to precipitateasphalticconstituentsffrom the oil. Y

The invention has application to thedeasphalting of mineral lubricatingoil stocks with asolvent comprising liquiiied normally gaseoushydrocarbons such as propane, .butana'ormixtures thereof.

In -accordance with the invention, the treatment of the feed oil iseected during passage through a series of settlingand'separating-'stages arranged in series. The fresh feed oil isintroduced to an intermediate vstage of: the' series wherein it issubjected to contact with the solvent in suitable proportions and at asuitable temperature level so as to effect separation into a lprimaryasphalt phase and a-primary oilfsolution phase. The resultingprimaryIasphaltphasegis removed and conducted'tovonezor more succeeding stagesin the series whereinitzis subjected to contact with additional 'solventfliquid at somewhat lower temperatures yso` as to effec-tseparation of retained oil from thefasphalticv and ,resinous material.The asphaltandresinous material mixed with some solvent is discharged-from theiinal stage of the series lwhile `oil solution removed from thesucceeding-stage orrstages is recycled to the aforesaidintermediatestage.

The primary oil-phase removed from the intermediate stage retains avsubstantial amount of resinous or soft asphaltic material and thisphase is conducted to a preceding or initial stage in the seriesmaintained at a more elevated temperature such that retainedresinousmaterialprecipitates from the solvent solution of oil. Theprecipitated material is conducted from the preceding stage tothe'aforesaid intermediate stage While the resulting deasphalted oilsolution is .separately withdrawn from the preceding stage and :passesto a stripping unit for recoveryl of solvent liquid.

A feature of the invention thus involves conincreasing ltheconcentration :ofithis-lresinouslmaterial in the feed oil in this mannerby asmuch as 200 to 300%. In this way' it isfoundthat .more eifectiveand rapid precipitation ioff, rasph'altic material issecured-withthe.result.ithatthefch'arge rate to a given yplant mayfbe:increased:bywasy -much as 50% for V.thesamequantity of circulatingsolvent.' In otherJ words vthensolvent''Jdosage may be decreasedfbyfrom' 2001a-100%". i `1 Another feature of the invention.involvesnrecycling of some deasphaltedfloilrtothezirritial or precedingstage of 'the series?l The amounttso recycled is correlated withtheftemperaturesmaintained in the.initialJstageparticularlywhenusing aAliquiiied normally gaseoushyd-rocarbonpzln order to maintainsuch asolvent liquiiied ataelevated temperatures, substantial!A pressure :isrequired which necessitates the employmentviof heavyequipment. t

The higher 4the temperatura-the morefinsoluble the resinousmaterial..,1t .appears,=x'how ever, that effective resinVseparationScan-abe.secured at somewhat lower"temperaturesabyk theaddition cf. some deasphalted f'oil=:f:to:-.the=: resin separatingstage.` The fadditionfiofnthis:oil'has the eect of v'displacingmore io'flthe relatively n insoluble material, :i. e;resinousfmaterialffromducting precipitated resinous-material from the 55. in the intermediatestage. j.It is contemplatedy the oil solution. Theamountloffrecycleoil-may range from about ,10i to l25% ofithe'primaryfphase oilenteringthe 'resinl separatingtstage. Iniorder lto describe the vmethod. of.`owrintmoreydetail,

reference will now bewmad'e @tot-theffiaccompanying drawing.

As indicated in the., drawing;ir az'seriesfof/.rseparating .stagesdesignated byY thefnumeralsvzl ,12, 3 and 4, respectively, may .beemployedrfxThese stages are merely `,represented-,in diagrammatic form,and any L suitable design fmaypbe employed which rpermits adequatemiXingL.-between: isolvent and oil and separation lof resulting'phases.Moreover, -additional stages may-abe providedalthough at least threestagesareessential.

An asphalt bearing charge ioil suchrfas t residual cylinder stockderived from Mid-Continent'crude is conducted from asource'notfshownfthrough a pipe 5 and a-pipe-(A to theintermediatefstage:2. A stream of solvent liquid, i. 'ef-propane .or/a propanefractiondrawnffrom astorage l,tank 8 through pipes 9 and l0 is conductedv:through a branch pipe l! and thusfinjectedgintothe charge roil streamflowing throughthe pipe 6. AInr` this way eifective mixing betweencharge oil-andsolvent is effected. The ysolvent mayy be injected in theproportion of about .5 to 9fvolumesoffso1- vent per volumeof *charge-oilThe mixture of t feedioil Sandi solvent yflows into stage 2 whereinseparation into phases occurs, the temperature being maintained withinthe range of about 135 to 155 F. and usually at about 145 to 150 F.Under such conditions, a primary asphalt phase is formed comprisingasphalt 'and resins mixed with a minor proportion of the,` solvent andsome oil, and a primary oil phase comprising oil and resinous materialor soft asphalt dissolved in the major portion of the about 10 to 20,ormore volumes of solvent for each volume of asphalt. f

The stage 3 is maintained at a temperature in the range of 125 to .135F., so that further separation between oil and asphalt occurs. Theseparated oil Vis continuously withdrawn through a pipe I6 and recycledto stage 2 as indicated, the recycled oil advantageously beingcommingled with the stream of oil and solvent flowing through thepipe 6.M. d ,v

The partially deoiled asphalt'phase formed in stage 3 is continuouslydrawn off through a pipe I1 to stage 4addition'al solvent equivalent toabout 50% kof the total solvent required for the treating operationbeing added through branch pipey I 8y so as toprovide a mixture of about20 to 40 volumes of solvent for each volume of asphalt.`

The resulting asphalt and resin mixture froml which retainedl oil hasbeen removed in stage 14 is continuously discharged through a pipe 20 toa stripper 2| wherein solvent is recovered from the asphalt and resinmaterial. The recovered solvent is returned through a pipe 22 to theaforesaid storage tank, 8.

The primary oil'phase accumulating ln stage 2 is continuously removedthrough a pipe 30 and conducted to a pipe 3| and a heater or heatexchanger 32, wherein it is raised to a temperature of about 160 F. Theresulting heated mixture of oil resin and solvent is introduced to stageIwhich is maintained at a temperature in the rangeof 155 to 165 F., andusually at about 160 F., so that precipitation of resins from the oilsolution occurs. If desired, some additional solvent maybe added fromthe pipe I through a branch -pipe 33. However, it is contemplated thatin the usual case,` additional solvent will not be required.

The resulting deresinied oil solution is continuously removed through apipe 34 and conducted to a stripper 35, wherein the solvent is recoveredfrom the deasphalted and deresined oil. The recovered solvent may bereturned through pipe 22 to the storage tank 8.

A small portion of the de-asphalted and deresined -oil may be recycledto pipe 3| for com- V'mingling withthe primary oil phase passage tostage I, and thus aid in the precipitation of resinous material from theoil.

The resin precipitate comprising about equal volumes of resinousmaterial and solvent is drawn olf through a pipe 4D, exchanger 4l andpipe 42 connecting with the previously mentioned pipe 6 through which itis conducted to stage 2. The exchanger 4I may be by-passed all or inpart if desired by a pipe 43.

The resin precipitate flowing through pipe 40 is added to the charge oilmixture passing to stage 2 so as to aid in obtaining more effective andrapid precipitation of asphalt and resin from the oil.

By way of example, when treating a residual cylinder stock derived fromMid-Continent crude, characterized by having an A. P. I. gravity of 2l,Saybolt Universal viscosity of 220 seconds at 210 F. and a carbonresidue content of 5.2%, a deasphalted and de-resined lubricating oilstock amounting to at least of the charge oil is obtained, employingconditions of temperature and solvent dosage previously indicated. Thelubricating stock so obtained has an A. P'. I. gravity of about 24.2, acarbon residue content of about 1.50, and a color of about 11/8Tag-Robinson, or higher.

By contrast, when treating the same type of feed oil under similarconditions of temperature and increased solvent dosage but withoutrecycling the resin precipitate from stage I and resin bearing streamsof solvent from stages 3 and 4 to stage 2, only about 83% ofde-asphalted and de-resined oil of substantially the same quality isobtained. In this latter case, the resin precipitate is merely washedwith additional solvent in a separate stage, for example, stage 4, whilethe asphalt stream from the preceding stage 3 is passed directly to asolvent recovery unit.

While the employment of elevated pressures has not been referred tospecifically in describing the process, nevertheless, it is contemplatedthat suiiicient pressure is employed in the system to maintainsubstantially liquid phase conditions throughout the successive stages.

Also, while mention has been made of using a liquied normally gaseoushydrocarbon as the solvent, it is contemplated that other de-asphaltingsolvents or agents may be employed as for examp1e,aliphatic alcoholssuch as propyl, isopropyl, butyl, or isobutyl alcohols, mixturesthereof, etc.

It is contemplated that the invention has application to the treatmentof other than mineral type oils for the purpose of effecting separationof resinous or higher molecular weight constituents. It may be appliedto the treatment of fatty type oils derived from vegetable and animalsources. l

Obviously many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof,y and therefore only such limitations should beimposed as are indicated in the appended claims.

I claim:

1. A continuous method of separating asphaltic and resinous constituentsfrom residual lubricating oil stock containing both asphalt and resin insubstantial amounts by treatment with a liquefied normally gaseouspetroleum C3 and higher hydrocarbon solvent in a series of stages, whichcomprises passing a stream of feed oil mixed with from about 5 to 9volumes of said liquefied solvent per volume of feed oil to the secondstage in said series, said stage being maintained at a temperature ofabout 135 to 155 F., effecting separation therein into two primaryliquid phases, one of said phases comprising an asphalt phase and theother comprising an oilsolvent phase retaining resinous material,separately withdrawing said primary phases, passing withdrawn primaryoil-solvent phase to the preceding stage, subjecting said primaryoil-solvent phase to settling therein at a temperature of about 155 to165 F. such that retained resinous material precipitates therefromleaving substantially deasphalted and deresined oil, dischargingresulting deasphalted and deresined oil from said preceding stage,injecting said precipitated resins into said stream of feed oil passingto said second stage in amount suilicient to increase the concentrationof resins into said feed stream by about 200 to 300%, passing saidprimary asphalt phase mixed with solvent in the proportion of about 10to 20 volumes per volume of asphalt to the third stage of the seriesmaintained at a temperature of about 125 to 135 F. such that furtherseparation into oil and asphalt phases occurs, separately withdrawingthird stage oil and asphalt phases respectively, recycling withdrawnthird stage oil to said second stage, passing withdrawn third stageasphalt to a final stage, subjecting it to contact in said final stagewith about 20 to 40 volumes of solvent per volume of asphalt at atemperature of about 120 to 130 F. thereby effecting substantiallycomplete deoiling of asphaltic and resinous material, dischargingresulting deoiled material, and recycling resulting ol solution fromsaid final stage to said third stage.

2. The method according to claim 1 in which,

a small portion of deasphalted and deresined oil is recycled to saidpreceding stage.

3. A continuous method of separating asphaltic and resinous constituentsfrom residual cylinder stock derived from Mid-Continent crude containingboth asphalt and resins in substantial amounts by treatment with asolvent comprising essentially liquefied propane in a series of stagesthereby obtaining a lubricating oil stock having a Tag-Robinson color of11A; and higher which comprises passing a stream of said cylinder stockfeed oil with from about 5 to 9 volumes of said solvent per volume offeed oil to the second stage in said series, said stage being maintainedat a temperature of about to 155 F., effecting separation therein intotwo primary liquid phases, one of said phases comprising an asphaltphase and the other comprising an oilsolvent phase retaining resinousmaterial, separately withdrawing said primary phases, passing withdrawnprimary oil-solvent phase to the preceding stage, subjecting saidprimary oil-solvent phase to settling therein at a temperature of aboutto 165 F. such that retained resinous material precipitates therefromleaving substantially deasphalted and deresined oil, dischargingresulting deasphalted and deresined oil from said preceding stage,injecting said precipitated resins into said stream of feed oil passingto said second stage in amount sufficient to increase the concentrationof resins in said feed stream by about 200 to 300%, passing said primaryasphalt phase mixed with solvent in the proportion of about 10 to 20volumes per volume of asphalt to the third stage of the seriesmaintained at a temperature of about 125 to 135 F. such that furtherseparation into oil and asphalt phases occurs, separately withdrawingthird stage oil and asphalt phases respectively, recycling withdrawnthird stage oil to said second stage, passing withdrawn third stageasphalt to a final stage, subjecting it to contact in said final stagewith about 20 to 40 volumes of solvent per volume of asphalt at atemperature of about 120 to 130 F. thereby effecting substantiallycomplete deoiling of asphaltic and resinous material, dischargingresulting deoiled material, and recycling resulting oil solution fromsaid final stage to said third stage.

4. The method according to claim 3 in which a small portion of thedeasphalted and deresined cylinder stock is recycled to said precedingstage.

WYNKOOP KIERSTED, JR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,143,872 Forrest et al. Jan. 17,1939 2,143,882 Keith et al. Jan. 17, 1939 2,284,583 Lewis May 26, 19422,367,671 Dickinson et al. Jan. 23, 1945

1. A CONTINUOUS METHOD OF SEPARATING ASPHALTIC AND RESINOUS CONSTITUENTS FROM RESIDUAL LUBRICATING OIL STOCK CONTAINING BOTH ASPHALT AND RESIN IN SUBSTANTIAL AMOUNTS BY TREATMENT WITH A LIQUEFIED NORMALLY GASEOUS PETROLEUM C3 AND HIGHER HYDROCARBON SOLVENT IN A SERIES OF STAGES, WHICH COMPRISES PASSING A STREAM OF FEED OIL MIXED WITH FROM ABOUT 5 TO 9 VOLUMES OF SAID LIQUEFIED SOLVENT PER VOLUME OF FEED OIL TO THE SECOND STAGE IN SAID SERIES, SAID STAGE BEING MAINTAINED AT A TEMPERATURE OF ABOUT 135 TO 155* F., EFFECTING SEPARATION THEREIN INTO TWO PRIMARY LIQUID PHASES, ONE OF SAID PHASES COMPRISING AN ASPHALT PHASE AND THE OTHER COMPRISING AN OILSOLVENT PHASE RETAINING RESINOUS MATERIAL, SEPARATELY WITHDRAWING SAID PRIMARY PHASES, PASSING WITHDRAWN PRIMARY OIL-SOLVENT PHASE TO THE PRECEDING STAGE, SUBJECTING SAID PRIMARY OIL-SOLVENT PHASE TO SETTLING THEREIN AT A TEMPERATURE OF ABOUT 155 TO 165*F. SUCH THAT RETAINED RESINOUS MATERIAL PRECIPITATES THEREFROM LEAVING SUBSTANTIALLY DEASPHALTED AND DERESINED OIL, DISCHARGING RESULTING DEASPHALTED AND DERESINED OIL FROM SAID PRECIDING STAGE, INJECTING SAID PRECIPITATED RESINS INTO SAID STREAM OF FEED OIL PASSING TO SAID SECOND STAGE IN AMOUNT SUFFICIENT TO INCREASE THE CONCENTRATION OF RESINS INTO SAID FEED STREAM BY ABOUT 200 TO 300% PASSING SAID PRIMARY ASPHALT PHASE MIXED WITH SOLVENT IN THE PROPORTION OF ABOUT 10 TO 20 VOLUMES PER VOLUME OF ASPHALT TO THE THIRD STAGE OF THE SERIES MAINTAINED AT A TEMPERATURE OF ABOUT 125 TO 135*F. SUCH THAT FURTHER SEPARATION INTO OIL AND ASPHALT PHASES OCCURS, SEPARATELY WITHDRAWING THIRD STAGE OIL AND ASPHALT PHASES RESPECTIVELY, RECYCLING WITHDRAWN THIRD STAGE OIL TO SAID SECOND STAGE, PASSING WITHDRAWN THIRD STAGE ASPHALT TO A FINAL STAGE, SUBJECTING IT TO CONTACT IN SAID FINAL STAGE WITH ABOUT 20 TO 40 VOLUMES OF SOLVENT PER VOLUME OF ASPHALT AT A TEMPERATURE OF ABOUT 120 TO 130*F. THEREBY EFFECTING SUBSTANTIALLY COMPLETE DEOILING OF ASPHALTIC AND RESINOUS MATERIAL, DISCHARGING RESULTING DEOILED MATERIAL, AND RECYCLING RESULTING OIL SOLUTION FROM SAID FINAL STAGE TO SAID THIRD STAGE. 